BIOTREATMENT OF WATERS CONTAMINATED WITH COMMERCIAL NAPHTHENIC ACIDS
| dc.contributor.committeeMember | Evitts, Richard | |
| dc.contributor.committeeMember | Niu, Catherine | |
| dc.contributor.committeeMember | McPhedran, Kerry | |
| dc.creator | Zanjani, Hamid 1986- | |
| dc.date.accessioned | 2019-08-02T22:23:24Z | |
| dc.date.available | 2019-08-02T22:23:24Z | |
| dc.date.created | 2019-07 | |
| dc.date.issued | 2019-08-02 | |
| dc.date.submitted | July 2019 | |
| dc.date.updated | 2019-08-02T22:23:25Z | |
| dc.description.abstract | Extraction of bitumen and production of heavy oil from oil sands play a crucial role in the economy of Canada. Processing of oil sands, however, results in the generation of large amounts of contaminated waters (oil sands process-affected water, OSPW) that are currently stored in tailing ponds. These waters and associated tailing ponds are one of health and environmental challenges associated with oil sands; and efforts in the remediation of these contaminated and toxic waters are urgently required. Toxicity of contaminated waters (OSPW) has been attributed mainly to the presence of naphthenic acids (NAs). Different physicochemical and biological approaches have been used for removal of NAs present in the OSPW. These methods include, but are not limited to, adsorption, advanced oxidation, coagulation/flocculation, membrane filtration, biodegradation, and combination of chemical and biological methods. However, much of the research up to now has been focused on the biodegradation pathways, effect of NAs on biodegradation extent, and comparison of different removal methods and little attention has been paid to impact of operating parameters for improving the treatment efficiency. Therefore, this study was set out to explore this missing link. In the work presented here, an experimental study on biodegradation of NAs was conducted in batch bioreactors and circulating packed bed bioreactors (CPBBs) that aimed to verify the impact of various parameters like initial concentration, temperature, and loading rate on biodegradation of commercial NAs and included evaluation of individual NAs distribution and toxicity. It is expected that understanding of aerobic biodegradation of commercial NAs will lead to the development of suitable technologies to address this environmental concern. Through the batch experiments, the effect of various parameters including concentration (50, 100, 150, 200 mg NA L-1), and temperature (20, 24, 28, 35 ℃) were studied. Maximum biodegradation rates in the batch system were achieved during the biodegradation of NAs with the highest concentration (0.78 mg TOC L-1 h-1 at 200 mg TOC L-1 and 28 ℃) (TOC: Total organic carbon). It was also observed that temperature variation did not significantly affect the biodegradation of commercial NAs. Gas chromatography-electron impact–mass spectrometry analysis was used to track the changes in NA mixture profiles, or “fingerprints,” for each condition over time. Using this analysis, more rapid degradation was observed for NAs that had lower carbon numbers and fewer degrees of cyclization. In continuous packed bed bioreactors (CPBBs), increasing the NA concentration and loading rate led to higher removal rate, while removal percentage was declined. The maximum biodegradation rate of 128.0, 321.7, 430.2, and 630.0 mg TOC L-1 h-1 and removal percentages of 76.3, 87.6, 89.1, and 82.5% were achieved with influent NA concentrations of 50, 100, 150, and 200 mg NA L-1, respectively. GC-MS compositional study of CPBB effluents showed that low molecular weight NAs were most amenable to biodegradation where for instance at influent concentration of 50 mg NA L-1 and loading rate of 7 mg TOC L-1 h-1 the removal percentage was 83.1, 81.0, and 74.7 for light, medium, and heavy NAs. It was also observed that NAs cyclicity had a direct effect on the removal percentage of NAs. The results of V. fischeri and A. salina toxicity analyses indicated that biodegradation in CPBB reduced the toxicity of NAs contaminated water. This reduction depended on the loading rate and influent concentration. At influent concentration of 100 to 200 mg NA L-1, IC50 of 7.6 and 4.0% improved to 78.1 and 68.5% at the lowest loading rates and 41.7 and 36.5% at the highest loading rates, respectively. | |
| dc.format.mimetype | application/pdf | |
| dc.identifier.uri | http://hdl.handle.net/10388/12240 | |
| dc.subject | Naphthenic Acid | |
| dc.subject | Bioremediation | |
| dc.subject | Toxicity | |
| dc.subject | Circulating packed bed bioreactor | |
| dc.title | BIOTREATMENT OF WATERS CONTAMINATED WITH COMMERCIAL NAPHTHENIC ACIDS | |
| dc.type | Thesis | |
| dc.type.material | text | |
| thesis.degree.department | Chemical and Biological Engineering | |
| thesis.degree.discipline | Chemical Engineering | |
| thesis.degree.grantor | University of Saskatchewan | |
| thesis.degree.level | Masters | |
| thesis.degree.name | Master of Science (M.Sc.) |